Negative differential resistance behavior in molecular devices based on carbon nanotubes: Effects of chirality and electrode–electrode distance

Using first-principles density functional theory and real-space non-equilibrium Green′s function formalism for quantum transport calculation, we investigate all-carbon mechanically controlled molecular devices which consists of only two (5,5) armchair and two (6,0) zigzag single-walled carbon nanotubes (SWCNTs) opposing one another. Our results show that the chirality of SWCNTs and the electrode–electrode distance have crucial effects on the electronic transport properties of such systems. When the right SWCNT electrode is mechanically pushed forward along its axial direction, obvious negative differential resistance behaviors are observed in the zigzag system, but not in the armchair case.